Genotype ✕ Environment Interactions on Soft White Winter Wheat Quality

Enhanced quality is essential to improve marketability of northwestern USA soft white winter (SWW) wheat (Triticum aestivum L.). The objectives were to compare four major SWW cultivars for six quality criteria and their relative environmental stabilities. Cultivars Daws, Lewjain, Nugaines, and Stephens were grown in 63 site years and evaluated for flour yield, cookie diameter, percent flour protein, alkaline water retention capacity (AWRC), hardness, and sedimentation. Cultivar and environmental effects were significant (P<0.0l) for all traits. Genotype ✕ environment interactions were small, but significant. Among the variance components, years contributed most to total variance for percent protein, sedimentation, and AWRC. The year ✕ site component was greatest for flour yield, cookie diameter, and hardness. Relatively large cultivar ✕ environment components for cookie diameter, hardness, and AWRC required their evaluation across multiple site years. All cultivars had satisfactory overall SWW wheat quality, yet Lewjain and Stephens had the best cookie diameter and flour yield, respectively. Daws was marginal for cookie diameter and hardness, and Nugaines was usually low for flour yield. Stephens and Lewjain were generally the least and most sensitive to environmental variation for quality parameters. Most quality traits were correlated (P < 0.05) with each other within cultivars. The AWRC gave low and usually nonsignificant correlations with all quality parameters except cookie diameter. Intragenotypic differences in grain yield and grain volume weight were correlated (P < 0.05) with all quality traits except AWRC. Grain volume weight differences accounted for 26 to 40% and 36 to 67% of the variation in cookie diameter and flour yield, respectively. Contribution from USDA-ARS and College of Agric. and Home Econ. Res. Ctr., Washington State Univ.